The present invention relates to a device comprising a patch antenna, and coupling means for connecting the antenna to an electronic component such as a low noise amplifier (LNA), wherein the patch antenna is arranged on one side of an antenna plate.
In antennas for high-frequency applications the connection between the antenna and the first amplifier is very critical, since all losses which occur in this coupling have a negative effect on the reception sensitivity. According to a known coupling, a microstrip line is arranged on the underside of the ground plane of the patch antenna. At the position of this microstrip line a hole is made in the ground plane such that a capacitive coupling is realized between the microstrip line and the patch. Such a coupling has the drawback that not inappreciable stripline and impedance-mismatch losses occur. The matching of the impedances is moreover frequency-sensitive, so that such couplings cannot be properly matched over a determined bandwidth.
Another option consists of coupling by means of a whip antenna in a horn antenna. This coupling is however mechanically unstable and not suitable when a robust coupling is required. Another coupling option makes use of a direct clamping of two horn halves, wherein a ridge in the antenna is pressed against a track of the printed circuit board. Such a coupling has the drawback that corrosion problems occur, since the horn is manufactured from aluminium and the tracks on the printed circuit board are manufactured from copper or gilded. The two other stated options furthermore have the drawback that they are susceptible to ageing, whereby the signal losses increase over time.
U.S. Pat. No. 5,903,239 describes a device with a patch antenna which is arranged on one side of an antenna plate, and coupling means for connecting the antenna to an electronic component. The coupling means consist here of a passage and a microstrip line, and the electronic component is mounted on a second substrate mounted against the rear side of the antenna plate. Such a construction has the drawback that impedance-mismatch and substrate losses occur.